Presently, SIP is becoming an increasingly popular protocol for transporting both standard and non-standard information in a common framework over Internet Protocol (IP) based Local Area Networks (LANs), such as systems and services provided by AT&T. However, one drawback to the present SIP protocol is that the headers of SIP messages do not define a standard way to convey addressing and/or routing information.
The addressing and/or routing information is required for setting-up calls and/or for forming a multi-media communication path between a calling communication device and destination communication device. Since the SIP protocol and associated SIP messages do not define the parameters necessary to set-up calls or to form multi-media communication paths between the calling and destination communication devices, SIP cannot provide a standard way for signaling address and/or routing information between core network elements of the IP-based LAN.
Therefore, an unsolved need remains for a SIP protocol that provides SIP signaling messages, which are adapted for carrying address and/or routing related information necessary for providing signaling between core network elements of the IP-based LAN for setting-up calls and/or for forming multi-media communication paths between calling and destination communication devices.